For the purpose of the specification and claims, the term “slitting cutter” is intended to be inclusive of tools configured for slitting or slotting applications.
Within the field of slitting cutters, there are many examples of integral one-piece slitting cutters having a plurality of cutting teeth. FIGS. 1 and 2 show an integral one-piece slitting cutter 120 according to the prior art having an outer cutting diameter DO of 63 mm, a cutting width WC of 1 mm, and a plurality of 48 cutting teeth 142. Such a slitting cutter, may be limited to a maximum rotational speed of approximately 1260 rpm for slitting operations in a workpiece material such as spring steel, and has a simple tooth design devoid of chip forming capabilities, which may limit the feed rate per tooth to approximately 0.4 μm due to the associated high cutting forces. Such limitations may result in a feed rate per revolution of approximately 0.02 mm, and a feed rate per minute of 25-30 mm. Further disadvantages of integral one-piece slitting cutters are the short life-cycle and the reduced repeatability after regrinding.
Within the field of slotting cutters, typically having wider cutting widths than slitting cutters, there are many examples of disk-shaped cutting bodies having a plurality of insert receiving portions circumferentially spaced about the cutter body and a plurality of cutting inserts removably retained therein, which use a tool key to aid insertion and extraction of the cutting inserts.
U.S. Pat. No. 6,116,823 discloses a slot milling tool comprising a disc having a thickness in the range of 2-6 mm and a plurality of insert receiving seats circumferentially arranged around the periphery thereof, each insert receiving seat having a cutting insert retained therein by means of an elastically resilient projection defined by two cutting slots, the inner ends of the two slots being located significantly radially inward of the insert receiving seat.
U.S. Pat. No. 6,116,823 also discloses a tool used in combination with the slot milling tool, for insertion and extraction of the cutting inserts. The tool used for insertion and extraction of the cutting inserts has two cylindrical shaped pins, one of which is inserted into a hole adjacent the insert receiving seat and the other which is inserted into an opening formed at the outer end of one of the slots. Rotation of the tool around a fulcrum formed by the pin in the hole causes the other pin to lift the elastically resilient projection, thus providing sufficient space for insertion or extraction of the respective cutting insert.